TX200 Piston Seal

Discussion in 'Piston & Spring' started by EV2UK, Jan 3, 2019.

  1. EV2UK

    EV2UK Active Member

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    I recently bought a TX200 (not new)

    Have it in bits at the moment for a bit of a clean and the piston seal feels very hard...

    Is it best to replace it for an Air Arms standard one?
    Been looking on a big online auction site and have seen two for sale.. One of a tan colour and the other one clear... Are they different?

    Is Thwaite any point in fitting a 'different' seal and if so which one and where do I get one?

    I See the TBT short stroke kit uses a HW seal... Any benifit in one of these?


    Tony
     
  2. Brian.Samson

    Brian.Samson Allowed in Sales Staff Member

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  3. EV2UK

    EV2UK Active Member

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    Link isn't working brian.

    Has the compression tube inner diameter ever change over the years?
     
  4. Brian.Samson

    Brian.Samson Allowed in Sales Staff Member

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    Sorry, search eBay for 163420815033
    It's the Australian Gamo seal for the TX

    The comp tube ID has been 25mm since the Mk1 TX200.
     
  5. EV2UK

    EV2UK Active Member

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    Than you Brian.

    All ordered...
     
  6. hmangphilly

    hmangphilly Floppy Quick Phil

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    seal.jpg
     
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  7. Cooper_dan

    Cooper_dan Active Member

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    That blue gamo one is what I've been using for the last 6 months. Not had a single problem and rifle has been very stable through end of summer and the change to winter (more so than some people's tuned tx's).
    +1 from me

    It will be tight when fitting and it's possible to damage it on the sharp cone of the tx piston head. Drop it in very hot water for a few minutes to soften it up a bit first.
     
  8. imorik

    imorik Member

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    Using one as well. Took the sharp edge off the cone before fitting and used a smear of grease and it slips on............ eventually.
     
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  9. hmangphilly

    hmangphilly Floppy Quick Phil

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    The air gap between the end of the piston cone and the seal is interesting
     
  10. Cooper_dan

    Cooper_dan Active Member

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    I assume to account for the unknown tolerances of the cone height and major diameter? I doubt air arms would tell anyone what that tolerances are so aftermarket seals would need to be slightly oversized to ensure they always fit
     
  11. Brian.Samson

    Brian.Samson Allowed in Sales Staff Member

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    That isn't a TX200 piston in the photo.

    The gap might be that the seal is designed to fit a number of different pistons including the TX - it may be that it's a perfect fit on the TX. Dunno.
     
  12. hmangphilly

    hmangphilly Floppy Quick Phil

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    No
    I dunno either Mate .

    Yep I can see it's not a std tx piston .......it's nasty innit

    The pic came off the makers ebay listing , so I assumed ( we know what assuming does don't we ) that they had pictured it fitted to the piston that it was listed as fiiting ( not tx ) .

    Also assumed that the gap was deliberate and it got me thinking .....

    not saying it's a good thing or bad , just that it's interesting

    The bevel / chamfer / leade around the front end of the seal is interesting too.
    Counterintuitive to me , but I'm not a seal manufacturer .

    they give an explnation of it in the blurb but ........hmmmm....I dunno
     
    Last edited: Jan 4, 2019
  13. Dale

    Dale Active Member

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    As it is a seal for Gamo rifles best guess its a Gamo piston it is shown fitted to.

    Crappy standard of finishing on the piston though, whatever make it is.

    The blurb from the website:

    GAMO 25MM AIR RIFLE POWER SEAL
    NEW DESIGN
    •Sealed face for less lost volume and air loss + more power
    •Steep cut away taper for less seal contact and friction
    •Precision moulded from High Quality Polyurethane
    • Will Provide a modest power increase
    • Piston shown is NOT included

    THIS IS GAMO’S STANDARD 25MM AIR RIFLE PISTON SEAL . IT IS USED IN ALMOST ALL GAMO RIFLES AND MANY CLONES OF THIS DESIGN.

    GAMO PISTON SEAL ALSO FITS BSA MK 6 AND BAM B40 SMK

    FITS SOME CROSMAN BENJAMINE AND ALSO THE NEWER NITRO PISTON MODELS PLEASE MEASURE AND CHECK FITMENT

    DIANA 24 26 THAT REQUIRE A 25MM SEAL

    DIANA 240

    AND ANY OTHER AIR RIFLE WITH A 25MM CYLINDER AND A WEDGE SHAPED FITMENT.

    MADE FROM HIGH QUALITY MATERIAL WHICH WILL PRODUCE A SUPERIOR SEAL WHEN COMPARED TO THE HARD AND CHEAPLY MANUFACTURED GAMO FACTORY SEAL.

    PROVIDES A BETTER SEAL AND MORE POWER THAN OEM SEAL. MOST GAMO SEALS ARE DAMAGED ON INSTALL AT FACTORY.

    PLEASE DE-BURR YOUR COCKING SLOT TRIGGER CUT OUT AND CROSS PIN HOLE BEFORE INSTALLING PISTON AND SEAL

    USE A SMALL AMOUNT OF MOLY LUBE ON THE PISTON NO LUBE SHOULD BE ON THE PISTON FACE
     
    Last edited: Jan 4, 2019
  14. tazvmax

    tazvmax Member

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    I have one fitted to my TX200 mk 3 it is giving very consistent power results ie 756.8 to 763.2 fps over 10 shots with 8.44 JSB 4.52 exact diablo.
    The gun is standard apart from having the delron spring guide machined into the trigger block.
     
  15. Nomads HFT

    Nomads HFT Well-Known Member

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    You're right to be sceptical. Phil.

    Kinetic (sliding) friction is independent of contact area.
     
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  16. RobF

    RobF Administrator Staff Member

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    Yes we were having this discussion just the other day regarding hammer diameter. The initial thought was that a greater diamter had a greater contact and had more friction. In actual fact it's contact pressure which creates the friction, so if you increase the surface area then the pressure drops because the force is spread over a greater area... thus friction remains the same.

    The only way to combat that is to improve the surface finish, rough obviously sliding less well then smooth. But with plastic seals and other materials there's a limit how well they can be finished/smoothed, so the variation will be come less the more you chase it. You're effectively chasing the most slippery material combination which isn't affected by heat variations and can last.
     
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  17. Brian.Samson

    Brian.Samson Allowed in Sales Staff Member

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    Of course you've all missed the most obvious problem with the photo of the seal. It won't seal very well at all because it's been cut in half :D
     
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  18. Alanok2002

    Alanok2002 Member

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    I think this is the same seal the current ft world champ uses and rates
     
  19. FPoole

    FPoole Active Member

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    And it also won't hold and pull itself down as tightly on the dovetail, being only half.
     
  20. RobF

    RobF Administrator Staff Member

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    It's held in by place by the compression tube around it, duh... :D
     

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